diff --git a/.eslintrc.js b/.eslintrc.js
index 2e7e98394..317092ad5 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -19,6 +19,8 @@ module.exports = {
     'arrow-parens': 0,
     // allow async-await
     'generator-star-spacing': 0,
+    // allow hasOwnProperty
+    'no-prototype-builtins': 0,
     // allow debugger during development
     'no-debugger': process.env.NODE_ENV === 'production' ? 2 : 0,
     'no-console': process.env.NODE_ENV === 'production' ? ['error', { "allow": ["error"] }] : 'off',
diff --git a/frontend/js/components/LocationField.vue b/frontend/js/components/LocationField.vue
index fa3a29fa8..4f359f51f 100755
--- a/frontend/js/components/LocationField.vue
+++ b/frontend/js/components/LocationField.vue
@@ -42,6 +42,8 @@
   const GOOGLEMAPURL = 'https://maps.googleapis.com/maps/api/js?libraries=places&key='
   const APIKEY = window[process.env.VUE_APP_NAME].hasOwnProperty('APIKEYS') && window[process.env.VUE_APP_NAME].APIKEYS.hasOwnProperty('googleMapApi') ? window[process.env.VUE_APP_NAME].APIKEYS.googleMapApi : null
 
+  /* global google */
+
   export default {
     name: 'A17Locationfield',
     mixins: [InputMixin, InputframeMixin, LocaleMixin, FormStoreMixin],
@@ -204,7 +206,7 @@
       toggleMap: function () {
         this.isMapOpen = !this.isMapOpen
         this.mapMessage = this.isMapOpen ? MAPMESSAGE.hide : MAPMESSAGE.show
-        /* global google */
+
         if (!this.map && typeof google !== 'undefined') {
           this.$nextTick(function () {
             this.initMap()
@@ -239,7 +241,6 @@
         // Create the autocomplete object and associate it with the UI input control.
         this.autocompletePlace = new google.maps.places.Autocomplete(this.$el.querySelector('input[type="search"]'))
         // When a place is selected
-        /* global google */
         google.maps.event.addListener(this.autocompletePlace, 'place_changed', this.onPlaceChanged)
 
         if (this.address === '' && this.lat && this.lng) {
@@ -270,7 +271,6 @@
       }
     },
     mounted: function () {
-      /* global google */
       if (typeof google !== 'undefined') {
         this.initGoogleApi()
       } else {
@@ -283,7 +283,6 @@
       }
     },
     beforeDestroy: function () {
-      /* global google */
       if (typeof google !== 'undefined') google.maps.event.clearListeners(this.autocompletePlace, 'place_changed', this.onPlaceChanged)
     }
   }
diff --git a/frontend/js/components/Slideshow.vue b/frontend/js/components/Slideshow.vue
index 5af54097e..14044fdba 100755
--- a/frontend/js/components/Slideshow.vue
+++ b/frontend/js/components/Slideshow.vue
@@ -2,7 +2,7 @@
   <div class="slideshow">
     <draggable class="slideshow__content" v-model="slides" :options="dragOptions" v-if="slides.length">
       <transition-group name="draggable_list" tag='div'>
-        <div class="slide" v-for="(slide, index) in slides" :key="index">
+        <div class="slide" v-for="(slide, index) in slides" :key="slide.id">
             <div class="slide__handle">
               <div class="slide__handle--drag"></div>
             </div>
diff --git a/frontend/js/utils/formDataAsObj.js b/frontend/js/utils/formDataAsObj.js
index 6b66a0fc1..4c7e3d833 100755
--- a/frontend/js/utils/formDataAsObj.js
+++ b/frontend/js/utils/formDataAsObj.js
@@ -384,7 +384,6 @@ export default function (formNode) {
     let $domNode
     let domNodeValue
     const result = {}
-    let resultLength
 
     for (i = 0; i < $formElements.length; i++) {
       $domNode = $formElements[i]
@@ -433,7 +432,7 @@ export default function (formNode) {
     }
 
     // Check the length of the result.
-    resultLength = getObjLength(result)
+    const resultLength = getObjLength(result)
 
     return resultLength > 0 ? result : false
   }